Many boots, and particularly boots for sporting applications such as skiing, snowboarding, skating, hiking, and the like, are intended to be worn with a boot liner that fits inside the boot between the boot and the user's foot. The liner may be removable from the boot or permanently attached to the boot. The liner provides many benefits—for example, a liner conforms to the shape of the user's foot, providing a more exact fit between the user and the boot. The liner also helps to keep the user's foot warm, provides padding to the user, absorbs accumulated perspiration and other moisture, and provides a comfortable, snug fit between the user's foot and ankle and the boot. Removable liners have the advantage of being easily cleaned and replaced, as needed. Frequently, liners are provided with a relatively stiff and durable sole portion to protect the liner from excessive wear.
Prior art boot liners may be simply sock-type liners wherein the liner is generally L-shaped and tubular, with sufficient stretchability and flexibility to receive the user's foot. These types of liners can be difficult for the user to put on and take off. Often, a longitudinal vamp comprising a slit and tongue is provided in the liner to facilitate putting on the liner and boot. Conventional liners generally rely on the boot fastening system, e.g., laces and buckles, to provide a comfortably tight fit between the liner and the user. The boot fastening system may not be adequate for achieving the desired fit for the liner, however, because the boot is generally of a much stiffer construction than the liner.
Addressing this need, some prior art boot liners have a conventional vamp portion and separate tightening systems, such as laces or straps. Such laces or straps permit the liner to be fastened about the foot and ankle of the user at a selective tightness. This enables the user to achieve a more comfortable fit. Additionally, this vamp-type construction permits a greater range of options for the material that is used for the liner, since the liner does not have to be as stretchable as a sock-type liner. This greater choice in materials permits the designer greater options in selecting materials that are more suitable to meet the various functions of the liner described above. Such prior art liners, however, have the disadvantage that the user must lace up two sets of footwear, and the user typically cannot adjust the tightness of the liner without first unlacing and/or removing the outer shell to reach the liner lacing. Therefore, if the user determines the liner is too tight or too loose during use of the sports boot—for example, if the liner loosens during use—it may be inconvenient or impractical for the user to adjust the tightness of the liner. This can be especially problematic in snow sports such as skiing and snowboarding, where environmental conditions make it difficult for the user to remove his or her sports boots in situ. The user may also have to remove or loosen snow gaiters to remove the boot shell, further exacerbating the inconvenience. In fact, with prior art liner tightening systems, it is common for the snowboarder to make one or two runs down a slope, and then have to remove the boot shell to retighten the liner, then put the boot shell back on before making another run. This procedure is inconvenient and reduces the amount of time the user has to actually snowboard over any given day.
Lacing systems for boot shells are known that utilize a cord, such as a lace, that is slidably disposed in lace guides such that the lace crisscrosses the boot vamp, and a tightening mechanism having a spool attached to the boot, whereby the tightening mechanism can be easily accessed to tension the lace. For example U.S. Pat. No. 5,934,599, to Hammerslag (which is hereby incorporated by reference), discloses such a lacing system wherein the tightening mechanism is externally disposed on the back of the boot upper. Such systems, however, require a suitable external surface for mounting the tightening mechanism.
There remains a need, therefore, for a boot liner that incorporates a separate tightening system and wherein the liner can be tightened without loosening or removing the associated boot, or without lifting or loosening the snow gaiter or the pants and exposing the boot to the environment.